Fuse holding apparatus

ABSTRACT

A fuse panel has openings in which fuse-receiving receptacles of various fuse holder assemblies are mounted. Each of the receptacles is adapted lockingly to receive a fuse-carrying unit which when fully mounted within the associated receptacle presents an outer front face adjacent to the plane of the panel and having a projecting portion preferably at the bottom thereof. Each fuse-carrying unit has a hollow shank portion in which is removably held a fuse which projects from the fuse-carrying unit. When the projecting portion at the bottom of the front face of a fuse-carrying unit is pressed, the fuse-carrying member snaps outwardly to a degree where the fuse-carrying unit can be readily grasped to remove the entire unit and the attached fuse from the associated receptacle. The front faces of the various fusecarrying members are distinctively color coded to identify what particular parts of the circuits involved the fuses are located.

Q United States Patent [151 3,659,252 Brown [4 1 Apr. 25, 1972 54] FUSE HOLDING APPARATUS FOREIGN PATENTS OR APPLICATIONS [72] Inventor; William L, Brown, Lake Zurich 1. 76,619 10/1961 France ..339/208 [73] Assignee: Littelfuse, Inc., Des Plaines, 111. primary Emmine, Richa1-d Moore [22] Filed: Aug 24 1970 AttorneyWallenstein, Spangenberg, Hattis & Strampel [21] Appl. No.: 66,479 [57] ABSTRACT A fuse panel has openings in which fuse-receiving receptacles [52] U.S. Cl ..337/20l, 337/196, 339/113 L, of various fuse holder assemblies are mounted. Each of the 339/128, 339/147 R receptacles is adapted lockingly to receive a fuse-carrying unit [51] lnt.Cl ..H0lr 13/68 which when fully mounted within the associated receptacle [58] -Field of Search ..337/201, 194, 196, 198, 212; p s nts an uter front face adjacent to the plane of the panel 339/113, 126, 147, 128, 208, 209 and having a projecting portion preferably at the bottom thereof. Each fuse-carrying unit has a hollow shank portion in l 5 References Cited which is removably held a fuse which projects from the fusecarrying unit. When the projecting portion at the bottom of UNITED STATES PATENTS the front face of a fuse-carrying unit is pressed, the fuse-carrying member snaps outwardly to a degree where the fuse-carryg g 2/ g i ing unit can be readily grasped to remove the entire unit and 4/1 t 201 X the attached fuse from the associated receptacle. The front 3:252:32? 51323 3232;a it:311313111111331:3113391128 X ieeee ei iiie iiee-eeiieiiie membeie eieiiieiieeie color coded to identify what particular parts of the circuits involved the fuses are located.

23 Claims, 8 Drawing Figures PATENTEDAPR 25 1912 3. 659,252

SHEET 2 CF 2 luvan-roa WILLIAM L. 820w FUSE HOLDING APPARATUS This invention relates to fuse holders and to an arrangement of fuse holder assemblies on a panel which can be exposed to view. l-Ieretofore, panel mounted fuse holders generally have been provided' with fuse-carrying units lockable in or removable from the sockets of fuse-receiving receptacles by rotating a knurled head of a fuse-carrying unit in one direction or the other within the receptacle socket. The knurled heads of these fuse holder assemblies are so unsightly and offer a sufficient bumphaz'ard when placed in a position on the control panel of electrical equipment that it has been the practice generally to mount such fuse holder assemblies out of sight where they are less accessible.

The present invention represents a major advance in fuse holder design and construction in a number of respects. In the first place, the fuse holder assembly is preferably constructed in a manner which substantially reduces the manufacturing cost thereof independently of any other considerations. In the second place, the fuse-carrying unit, independently of any particular constructional details, is designed so that it can be mounted and locked in place in its receptacle by the simple expedient of inserting the unit into its receptacle and pushing on one portion of the front face of the fuse-carrying unit to fully insert the same within the receptacle,and pressing preferably another portion of said front face to release the fuse-carrying unit from its receptacle. In the third place, the fuse holder assemblies of the invention are most desirably constructed so that the front face of the fuse-carrying unit is in a plane contiguous to the plane of the mounting panel so that the fuse does not project substantially from the panel where it can form a hazard should a person bump into the same and so that the fuse holder presents an exceedingly attractive appearance, making it convenient and desirable to mount the same on an exposed panel. When said another portion of the front face of a fuse-carrying unit is pressed to release the same from its receptacle, the fuse-carrying 'unit pops-out of the fuse receptacle to a degree where it can be readily grasped and removed from the receptacle.

Each of the fuse holder receptacles most advantageously has a bezel frame (preferably of a rectangular shape) surrounding the panel opening in which it is mounted, which bezel frame has a size to extend beyond the outer periphery of the front face of the fuse-carrying unit (also preferably of a rectangular shape). In such an arrangement, various combinations of colors can be applied to the front faces of the fuse-carrying units and the bezel frames of the various fuse receptacles to provide a large number of possible color codes to identify the particular portions of the circuit or circuits in which the fuse of each fuse holder assembly is inserted. Also, such color coding presents an exceedingly attractive appearance to a control panel containing such fuse holder assemblies.

The above described and other features and advantages of the invention will become apparent upon making reference to the specification to follow, the claims and the drawings wherein:

FIG. 1 is a view of a panel on which is supported a number of fuse holder assemblies incorporating the various features of the invention;

FIG. 2 is a horizontal sectional view through one of the fuse holder assemblies supported in the panel of FIG. 1, taken along section line 2-2 thereof; 3

FIG. 3 is a vertical sectional view through the fuse holder assembly shown in FIG. 1, taken along section line 3-3 thereof;

FIG. 4 is a horizontal sectional view through the fuse holder assembly shown in FIGS. 2 and 3, taken along section line 4- 4 in FIG. 1;

FIG. 5 is a fragmentary sectional view of the front portion of the fuse holder assembly shown in F IG. 3, as the front face of the fuse carrying unit thereof is depressed to :remove the same from its fuse-receiving receptacle;

FIG. 6 is a fragmentary horizontal sectional view through the rear portion of the fuse holder assembly of FIG. 3, taken along section line 6-6 thereof;

FIG. 7 is a transverse vertical sectional view through the fuse holder assembly of FIG. 3, taken along section'line 7-7 thereof; and

FIG. 8 is an exploded perspective view of the different parts making up the fuse holder assembly of FIGS. 2 through 6 before the parts are assembled.

Referring now more particularly to FIG. 1, a panel 2 is thereshown which may be a part of a control panel for electrical equipment exposed to view and having fuse holder assemblies 4-1, 4-2, 4-3, 4-4, 4-5, 4-6, 4-7 and 4-8 mounted to form two rows of such fuse holder assemblies. Each fuse holder assembly comprises a fuse-receiving receptacle 6 (see FIGS. 2 and 3) preferably of rectangular cross-section and which, for the most part, is located behind the panel 2. The front portion of the fuse-receiving receptacle 6 of each fuse holder assembly passes through a preferably rectangular opening 8 in the panel 2 and projects only a short distance forwardly of the panel 2. The fuse-receiving receptacle 6 includes a preferably rectangular bezel frame 10a which extends laterally beyond the marginal portion of the opening 8 at the front of the panel 2 and frames the front face 12 of a fuse-carrying unit 14. The fuse-carrying unit 14 carries, as illustrated, a conventional cylindrical fuse 16. In a manner to be described, the fuse-carrying unit 14 with the fuse 16 projecting rearwardly therefrom is insertable into the fuse-receiving compartment 15 of the receptacle 6 by inserting the fuse 16 and a preferably rectangular shank portion 14b of the fusecarrying unit 14 into a similarly shaped opening 15a at the front of the fuse-receiving compartment 15 and then pressing on the flat portion 12a of the preferably rectangular front face 12 of the fuse-carrying unit 14 to push the assembly of the fuse 16 and the fuse-carrying unit 14 to the fullest extent into the receptacle 6. In a manner to be explained, the fuse-carrying unit then becomes locked within the receptacle 6. With the fuse-carrying unit 14 in this position, the front face 12 of the fuse-carrying unit 14 is in a plane which is only slightly forwardly of the front edge of the associated bezel frame 10a, and so there is no convenient shoulder to enable the user to grasp the fuse-carrying unit to remove the same from the receptacle.

On the assumption that the panel 2 is vertically oriented, the front face 12 of each fuse-carrying unit 14 most advantageously has in addition to the vertical flat portion 12a which as illustrated occupies about the upper two-thirds of the face 12 a downwardly and forwardly inclining bottom marginal portion 12b forming a raised or projecting portion on the face which can be readily depressed. To remove a fuse-carry ing unit 14 from its associated receptacle 6, the user depresses the raised portion 12b at the bottom marginal portion of the face 12, whereupon the fuse-carrying unit pops-out of the receptacle 6, as shown in dashed lines in FIG. 5, so that the fuse-carrying unit 14 can be readily grasped and pulled from the receptacle 6. To inform the user as to the method of removal of a fuse-carrying unit 14 from its associated receptacle 6, it was found that this function is most easily communicated to the user by placing the indicia PRESS on an intermediate portion of the face 12 with an arrow 20 extending from the word PRESS and pointing to and terminating near the bottom margin of the raised portion 12b of the face 12.

Each of the bezel frames 10a of each receptacle 6 extends preferably equally laterally outwardly beyond the margins of the front face 12 of each fuse-carrying unit 14 to form a visible frame around each fuse-carrying unit front face 12. The different fuse holder assemblies 4-1, 4-2, 4-3, etc. are identified by color coding in various combinations of the front faces 12 and the associated bezel frames 10a to identify the particular parts of the circuit or circuits involved where filaments of the fuses 16 are located. FIG. 1 illustrates an example of the invention where each fuse-carrying unit front face 12 and its associated .bezel frame 10a except fuse holder 4-7 have contrasting colors. Also, as there illustrated, it is noted that the fuse holder assemblies 4-6 and 4-7 are distinguishable from one another in that the bezel frame of fuse holder assembly 4-6 contrasts in color with the front face 12 of the associated fuse-carrying unit while, as above indicated, the bezel frame 100 of the fuse holder assembly 4-7 is of the same color as the front face 12 thereof.

Although in accordance with the broader aspects of the invention, the fuse holder assembly can have a variety of internal terminal constructions and arrangements to adapt the same to fuses of various terminal constructions and arrangements, the most preferred exemplary form of the invention described and shown in the drawings is a fuse holder assembly designed to carry and receive a fuse 16 of a conventional cylindrical type which includes a cylindrical main body portion 16a through which a fuse filament 16b is visible, and terminal-forming end caps 16c-16d located at the opposite ends of the fuse. Referring now more particularly to FIGS. 2, 3 and 8, the fuse-carrying unit 14 in the most advantageous form of the invention comprises two parts, preferably a synthetic plastic molded part 14 forming head and shank portions 14a and 14b of the fuse-carrying unit 14. The shank portion 14b defines a rectangular socket 23 open at the rear thereof to receive a terminal-forming member 25 made of a suitable conductive metal. The terminal-forming member 25 snugly seats within the bottom of the socket 23 and engages the rear surface 27 of the head portion 14a of the fuse-carrying part 14. The terminal-forming member 25 has a bottom wall 28 with an outward tab 28 which springs into a recess 30 in the bottom wall 27 of the shank portion 14b of the fuse-carrying part 14 to lock the terminal-forming member 25 in place in the socket 23. The upper wall 29 of the shank portion 14b of the fuse-carrying part 14' has a slot 31 opening onto the rear edge of this wall to permit the passage of an upwardly and forwardly curving contact and latch-forming projection 33 extending from the top wall 35 of the terminal-forming member 25. The

minal-forming blade projects'rearwardly through the rear end portions of the channels 60-60 at 63-63. A hole 67 is formed at the projecting rear end portion thereof through which hole a wire may be passed and soldered to make electrical connection to the terminal-forming blade 64. Wall projections 68-68 (FIGS. 3 and 6) extend inwardly from the bottom walls -50 of the receptacle-forming parts 44-44 in slightly spaced relation to the rear walls 52-52 to form narrow laterally extending passageways 70-70 (as shown in FIG. 6) communicating with confronting longitudinally extending slots 69-69 extending through the rear walls 52-52. A relatively short terminalforming blade 71 having a straight rearwardly extending end portion 71a with a wire receiving opening 72' extends longitudinally through these confronting slots 69-69 in the rear walls 52-52' and then bend to form a transversely extending wall portion 711; where it extends through the confronting short passageways 70-70. The transversely extending portion 71b of the terminal-forming blade 71 initially has side wings 20 71c-7lc' (FIG. 8) which are in the plane of the laterally exterminal-forming member 25 has side walls 39 and 41 forming with the top and bottom walls 35 and 28 separate fingers of a clip for removably holding one of the terminal-forming end caps 16d of the fuse 16. When the fuse 16 is in position within the terminal-forming member 25 of the fuse-carrying part 14, most of the length of the cylindrical portion 16a of the fuse l6 and the other end cap 160 thereof are positioned rearwardly of the fuse-carrying unit 14.

The fuse-receiving receptacle 6 of each fuse holder assembly is, for economy in manufacture, preferably formed of a pair of confronting receptacle-forming parts 44-44 which are mostly mirror images of one another, and respectively include opposite side walls 46-46, top walls 48-48, bottom walls 50-50 and rear walls 52-52. Top, side and bottom walls 48-48, 46-46 and 50-50 terminate at the front thereof in outwardly extending wall portions forming respective outwardly extending flanges 55-55. The receptacle-forming parts 44-44' have corresponding channel-forming walls 57-57 extending longitudinally inwardly from the rear walls 52-52 thereof to define between them and the top walls 48-48 confronting channels 60-60 which pass at 63-63 through the rear walls 52-52. The channel-forming wall 57 has a tongue portion 57a (FIGS. 7 and 8) which extends beyond the abutment plane of the walls 48-48, 50-50 etc. to fitwithin the recess 57a in the channel-forming wall 57. Short channel-forming walls 61-61 (FIG. 3) spaced a short distance from the top walls 48-48 at a point spaced in front of the channel-forming walls 57-57' form confronting channels 62-62 in alignment with the channels 60-60. The short channel-forming walls 61-61 merge with shoulder-forming wall portions 63-63 (FIG. 4) which form longitudinal and lateral blade-positioning shoulders or surfaces 63a-63a, 6319-6312 and 63c-63c wh ic h respectively are engaged by longitudinal and lateral edge portions 66a-66ai66b-66b and 66c-6 6c of a terminal-forming blade 64 having wings 66-66 forming the lateral edge portions 66b-66b and an outwardly extending head portion 66". The terminal-forming blade 64 seats within the confronting channels 60-60 and 62-62. The head portion of the terminal-forming blade 64 (sometimes referred to as a connector terminal-forming portion thereof) contains an aperture 65, and the rear end portion of the tertending portion 71b, thewings then passing through openings 75-75 (FIG. 6) formed at the rear of recessed portions 46a-46a of the side walls 46-46 of the receptacle-forming parts 44-44. The wings 71c-71c of the terminal-forming blade 71 are then bent rearwardly within slots 76-76 formed in the side walls 46-46 fixedly to secure the rear portions of the receptacle-forming parts 44-44 together.

The recessed portions 4611-4641 of the side walls 46-46 form longitudinally extending shallow grooves extending all the way to the rear margin of the receptacle-forming parts involved, and terminate at the front in the flanges 55-55. The terminal-forming blade 71 has a longitudinally and forwardly projecting extension 78 around which isbent the end of a tapered coil spring 80 extending longitudinally within the rear of the compartment 15 of the receptacle 6. When the fuse-carrying unit 14 is inserted within the receptacle compartment 15, the inner fuse terminal end cap 160 engages and compresses the front end of the coil spring (which thus forms a connector terminal-forming means). When the fuse-carrying unit is fully inserted within the receptacle compartment 15, the aforementioned contact and latch-forming extension 33 of the terminal-forming part 25 snaps within the apertures 65 at the front end of the terminal-forming blade 64. The outward force exerted on the fuse by the compressed spring 80 forces the front edge of the contact and latch-forming extension 33 within the aperture 65 against the front defining wail of the aperture 65 as best seen in F IG. 3.

The front end portions of the receptacle-forming parts 44-44' are held together by a bezel-forming member 10 which may be a synthetic plastic molded part of the same or different color to the front face FACE 12 of the fuse-carrying part 14'. The bezel-forming member 10 includes a bezel frame 10a at the front thereof defining a rectangular opening 81 which is of approximately the same size as the outer dimensions of the portion of the receptacle 6 formed by the top, bottom and side walls 48-48, 46-46 and 50-50 of the confronting receptacle-forming parts 44-44. The bezel-forming member 10 has a pair of inwardly extending nibs 91-91 (FIG. 3) which snap into recesses formed by the confronting recess-forming portions 93-93 and 95-95 formed in the top and bottom walls 48-48 and 50-50 of the receptacle-forming parts 44-44'.

The bezel-forming member 10 has secured thereto a pair of rearwardly extending spring arms 97-97 (FIGS. 2 and 8) which slide within the grooves formed by the recessed portions 46a-46a of the side walls 46-46 as the bezel-forming member 10 is slid into a position in front of the receptacle body 6. The spring arms 97-97' have rearwardly and outwardly inclining front portions 97a-97a which intersect rearwardly and inwardly extending rear portions 97b-97b. The portions of the spring arms 97-97 adjacent the apexes 970-970 thereof project beyond the outermost surfaces of the side walls 46-46 to present a comiressiliile means for locking or holding the fuse holder assembly within one of the panel openings 8. Thus, as best shown in FIG. 2, when the receptacle 6 is fully mounted within a panel opening 8 by pushing the rear portion thereof through the panel opening 8 from the front thereof, the rear face 103 of the bezel frame 10a engages the front face of the panel 2 and the spring arms 97-97 are sprung outwardly behind the panel 2 so :the apexes 97c-97c thereof are at a point beyond the margins of the panel opening 8, thereby providing an abutment shoulder preventing the ready removal of the receptacle 6 without the application of a substantial forward force.

The inner surfaces 5011-500 of the bottom walls 50-50 of the receptacle-forming parts 44-44 intersect at the front end thereof with forwardly and downwardly inclining surfaces 50b-50bq: which provide a clearance space 107 (see FIG. 3) below the shank portion 14b of the fuse-carrying unit 14 to permit the shank portion thereof to be rocked in a downward direction by depression of the raised portion 12b of the front face 12 of the fuse-carrying unit 14, as shown in FIG. 5. Such a downward rocking motion applied to the fuse-carrying unit 14 will pull the contact and latch-forming projection 33 of the terminal-forming member 25 out of the aperture 65 of the contact-forming blade 64, whereupon the coil spring 80 pushes the fuse-carrying unit 14 forwardly to cause the head portion 14a thereof to project substantially beyond the bezel frame 10, as shown in dashed lines in FIG. 5 where said head portion can be readily grasped to remove the fuse-carrying unit with the fuse attached thereto readily from the receptacle 6.

With the construction of the fuse holder assembly just described, the fuse holder assembly can be made at a substantially lower cost than the fuse holder assemblies having constructions heretofore utilized In addition, the fuse holder assembly of the invention has the various functional and omamental advantages described above.

it should be understood that numerous modifications may be made in the most preferred form of the invention described without deviating from the broader aspects of the present invention.

lclaim:

1. In a fuse holder assembly for holding a fuse with spaced terminals and to be mounted in or behind an opening in a panel, the fuse holder assembly including a fuse-receiving receptacle including means for mounting the same behind an opening in a panel where the receptacle, for the most part, is physically located behind the panel, a fuse-receiving compartment in said receptacle which opens onto the front of the receptacle, said receptacle compartment having first terminal means with a portion accessible from the outside of the receptacle at a point which is to be located behind said panel and second terminal means including a portion accessible from the outside of the receptacle at a point to be located behind said panel, the improvement comprising: a fuse-carrying unit with a head portion at the front thereof presenting a surface to be pressed by a users finger, a shank portion having an opening adapted to receive one end of said fuse and means for removably retaining said fuse in said opening and forming a terminal which engages one of said fuse terminals when the fuse is positioned therein, said last-mentioned terminal of said shank portion and the first and second terminal means of said fuse-receiving receptacle being so positioned that when said shank portion of said fuse-carrying unit is fully inserted into said open front end of said receptacle compartment the other terminal of said fuse is electrically connected to a portion of said first terminal means of said fuse-receiving receptacle and a portion of said terminal in the shank portion of said fuse-carrying unit engages a portion of the second terminal means of said fuse-receiving receptacle, said head portion of said fusecarrying unit when the unit is fully inserted into said compartment being contiguous to the front end of said fuse-receiving receptacle so the head portion thereof does not present any convenient shoulder for grasping and pulling the same from the fuse-receiving receptacle, and holding means on said fusecarrying unit and said fuse-receiving receptacle which lockingly holds said fuse-carrying member in said compartment of said fuse-receiving receptacle when the fuse-carrying unit is fully inserted into said compartment and which results in release and outward movement of said fuse-carrying unit when said surface of the head portion thereof is pressed by the end of the users finger, said outward movement of said released fuse-carrying unit permitting the same readily to be grasped and completely removed from said fuse-receiving receptacle.

2. The fuse holder assembly of claim 1 wherein there is provided spring means which is compressed when said fuse-carrying unit is inserted into said compartment of said fuse-receiving receptacle, said spring means causing said outward movement of said fuse-carrying unit when released from said fusecarrying receptacle.

3. The fuse holder assembly of claim 2 wherein said spring means forms part of said first terminal means in said compartment of said fuse-receiving receptacle.

4. The fuse holder assembly of claim 1 wherein said holding means include interlocking portions respectively of the terminal in said shank portion of said fuse-carrying unit and a portion of said second terminal means.

5. The fuse holder assembly of claim 1 wherein said finger pressed surface of said head portion of said fuse-carrying unit is a transversely extending face thereof of sufficient size to present at least two distinctly different areas to be readily engaged and pressed by the end of the user's finger, said holding means which lockingly holds said fuse-carrying unit in said compartment of said fuse-receiving receptacle effecting such locking action when one of said areas of said face of the fusecarrying unit is pressed and effecting the release and outward movement of said fuse-carrying unit when said other area thereof is pressed.

6. The fuse holder assembly of claim 5 wherein said areas of said face of said head portion of said fuse-carrying unit are in different planes.

7. The fuse holder assembly of claim 5 wherein said other area of said face of said head portion of said fuse-carrying unit is a raised portion.

8. The fuse holder assembly of claim 5 wherein there is provided spring means in said fuse-receiving receptacle compartment which is tensed as said fuse-carrying unit is fully inserted into said compartment, said holding means releasing said fusecarrying unit when said other area of said face of said head portion of said fuse-carrying unit is pressed, said spring means then forcing said fuse-carrying unit outward.

9. The fuse holder assembly of claim 7 wherein said raised portion extends to an outer margin of said face and there is indicia on said face of the head portion of said fuse-carrying unit which states that a portion thereof is to be pressed and there is an arrow on said face leading from said indicia and pointing to and terminating at or near said outer margin of said face.

10. The fuse holder assembly of claim 5 wherein said other area of said face extends to an outer margin of said face and there is indicia on said face of the head portion of said fusecarrying unit which states that a portion thereof is to be pressed and there is an arrow on said face leading from said indicia and pointing to and terminating at or near said outer margin of said face.

11. The fuse holder assembly of claim 7 wherein there is provided spring means in said fuse-receiving receptacle compartment which is tensed as said fuse-carrying unit is fully inserted into said compartment and which applies an outward force against said fuse-carrying unit when held in its locked position, said fuse-carrying unit being rockable about a laterally extending axis when said other area of said face of the head portion of said fuse-carrying unit is pressed, and said holding means comprises a resilient lateral projection on one of the fuse-receiving receptacle and fuse-carrying unit and a laterally facing opening in the other of same, said resilient lateral projection entering said laterally facing opening when the fuse-carrying member is initially fully inserted into said fuse-receiving receptacle compartment and which resilient lateral projection is moved out of said laterally facing opening when the fuse-carrying unit is rocked by the pressing of said other area of said face of the head portion of said fuse-carryin g member, whereupon said spring means causes longitudinal outward displacement of said resilient lateral projection from said laterally facing opening.

12. In a fuse holder assembly for holding a fuse with terminals on the opposite ends thereof, the fuse holder assembly to be mounted in or behind an opening in a panel, the fuse holder assembly including a fuse-receiving receptacle including means for mounting the same behind an opening in a panel where the receptacle, for the most part, is physically located behind the panel, a fuse-receiving compartment in said receptacle which opens onto the front of the receptacle, said receptacle compartment having first terminal means located at least in part in the rear end portion thereof which first terminal means has a portion accessible from the outside of the receptacle at a point which is to be located behind said panel, and second terminal means located at least in part in the front portion of said compartment and including a portion accessible from the outside of the receptacle at a point to be located behind said panel, the improvement comprising: a fuse-carrying unit with a head portion at the front thereof presenting a surface to be pressed by a users finger, and a hollow shank portion having an opening adapted to receive one end of said fuse and means for removably retaining said fuse in said opening and forming a terminal which engages the terminal at the adjacent end of the fuse when the fuse is positioned therein, said last-mentioned terminal and the terminal means of said fusereceiving receptacle being so positioned that when said shank portion of said fuse-carrying unit is fully inserted into said open front end of said receptacle compartment the terminal at the other end of said fuse engages a portion of said first terminal means of said fuse-receiving receptacle and a portion of said terminal in the shank portion of said fuse-carrying unit engages the portion of the second terminal means of said fusereceiving receptacle which is at the front portion of said receptacle, said head portion of said fuse-carrying unit when the unit is fully inserted into said compartment being contiguous to the front end of said fuse-receiving receptacle so the head portion thereof does not present any convenient shoulder for grasping and pulling the same from the fusereceiving receptacle, and holding means on said fuse-carrying unit and said fuse-receiving receptacle which lockingly holds said fuse-carrying unit in said fuse-receiving receptacle compartment when the fuse-carrying member is fully inserted into the compartment and which effects release and outward movement of said fuse-carrying unit when said surface of the head portion thereof is engaged and pressed by the end of the users finger, said outward movement of said released fusecarrying unit permitting the same readily to be grasped and completely removed from said fuse-receiving receptacle.

13. A fuse holder assembly for holding a fuse with spaced terminals on the opposite ends thereof, the fuse holder assembly to be mounted in or behind an opening in a panel, the fuse holder assembly comprising: a fuse-receiving receptacle including means for mounting the same behind an opening in a panel where the receptacle, for the most part, is physically located behind the panel, a fuse-receiving compartment in said receptacle which opens onto the front of the receptacle, said receptacle compartment containing a first terminal-forming member having an external circuit connecting portion exposed to the outside of said receptacle at a point thereof which,

is to be located behind said panel and a resilient connector terminal-forming means which is located at the rear end portion of said compartment, a second terminal-forming member in said compartment having an external circuit connecting portion exposed to the outside of said receptacle at a point thereof which is to be located behind said panel and having a connector terminal-forming portion positioned at the front end portion of said compartment; and a fuse-carrying unit with a head portion at the front thereof presenting a surface to be pressed by a users finger, and a hollow shank portion having an opening adapted to receive one end of said fuse and meansfor removably retaining said fuse in said opening and forming a terminal which engages one of said fuse terminals when the fuse is positioned therein, said last-mentioned terminal and the resilient connector terminal-forming means and said connector terminal-forming portion of said first and second terminal-forming members being so positioned that when said shank portion of said fuse-carrying unit is fully inserted into said open end of said receptacle compartment the terminal at the other end of said fuse engages said resilient connector terminal-forming means of said first terminal-forming member to deflect the same longitudinally inwardly, and a portion of said terminal in the shank portion of said fuse-carrying unit engages and interlocks with the connector terminalforming portion of said second terminal-forming member under the outward force of said resilient connector terminalforming means of said first terminal-forming member, said fuse-carrying unit when fully inserted into said receptacle compartment being pivotable in a direction which unlocks the interlocking portions of said terminal in the shank portion of said fuse-carrying unit and the connector terminal-forming portion of said second terminal-forming member, said head portion of said fuse-carrying unit when the unit is fully inserted into said receptacle compartment being contiguous to the front end of said fuse-receiving receptacle so that the head portion thereof does not present any convenient shoulder for grasping and pulling the same from the fuse-receiving receptacle, a portion of said surface on the head portion of said fusecarrying unit when depressed by the users finger effecting said rocking of the fuse-carrying unit to release the same under the force of said resilient connector terminal-forming means which causes outward movement of the released fusecarrying unit, permitting the same readily to be grasped and completely removed from said fuse-receiving receptacle.

14. In a fuse holder assembly for holding a fuse with terminals, the fuse holder assembly to be mounted in or behind an opening in a panel and including a fuse-carrying unit with a head portion adapted to be engaged by the users fingers and a shank portion having an opening adapted to receive one end of said fuse, and means for removably retaining said fuse in said opening and forming a terminal which engages one of said fuse terminals when the fuse is positioned therein, the fusecarrying unit with the fuse mounted therein respectively presenting front and rear terminals for electrically connecting the fuse terminals to an external circuit, the improvement in a fuse-receiving receptacle for removably receiving said fusecarrying unit and making electrical contact respectively with said front and rear terminals of said fuse-carrying unit when said fuse-carrying unit and fuse carried thereby is inserted therein, said receptacle comprising: a pair of laterally confronting receptacle body-forming parts defining therebetween a compartment which opens onto the front of said receptacle to receive the shank portion of said fuse-carrying unit, said compartment having a pair of terminal-forming members therein having respective external circuit connecting portions exposed to the outside of the receptacle at points to be located rearwardly of said panel, said pair of terminal-forming members respectively having connector terminal-forming portions positioned respectively at the front and rear portions of said compartment to make electrical engagement through said front and rear terminals of said fuse-carrying unit with the fuse mounted therein when the unit is fully inserted into said receptacle, and means for holding at least the front end portions of said confronting receptacle-forming parts together comprising a bezel-forming unit slidable along said confronting receptacle-forming parts to a position at the front of the receptacle where it interlocks therewith, the bezel-forming unit providing a frame around an opening in the panel in which the fuse holder receptacle is to be mounted.

15. The fuse holder assembly of claim 14 wherein said bezel-forming unit includes outwardly expanding contractable resilient wings which, when the receptacle is pushed through a panel opening from the front thereof, first contract and then spring outwardly to lock the fuse holder receptacle in place on the panel when the receptacle has been fully inserted into the panel opening.

16. The fuse holder assembly of claim wherein said confronting receptacle-forming parts have oppositely facing longitudinally extending side walls in which are formed longitudinally extending grooves opening onto the rear ends of the receptacle-forming parts, said wings extending from said bezel-forming unit have rearwardly and outwardly inclining front portions intersecting rearwardly and inwardly inclining rear portions to form respective apexes which are normally spaced apart a distance greater than the corresponding width of the opening of the panel in which the fuse holder receptacle is to be mounted and which when flexed inwardly can clear said opening, and said wings of the bezel-forming unit slidably fit within said longitudinally extending grooves in said side walls, said apexes of said wings normally projecting beyond the side margins of the receptacle.

17. The fuse holder assembly of claim 14 wherein said receptacle and fuse-carrying unit have a rectangular shape.

18. In a fuse holder assembly for holding a fuse with terminals, the fuse holder assembly to be mounted in' or behind an opening in a panel and comprising: a fuse-carrying unit with a head portion adapted to be engaged by the users fingers and a shank portion having an opening adapted to receive one end of said fuse, and means for removably retaining said fuse in said opening and forming a terminal which engages one of said fuse terminals when the fuse is positioned therein, the fuse-carrying unit with the fuse mounted therein respectively presenting front and rear terminals for electrically connecting the fuse terminals to an external circuit, the improvement in a fuse-receiving receptacle for removably receiving said fusecarrying unit and making electrical contact respectively with said front and rear terminals of said fuse-carrying unit when said fuse-carrying unit and fuse carried thereby is inserted therein, said receptacle comprising: a pair of laterally confronting receptacle body-forming parts defining therebetween a compartment which opens onto the front of said receptacle to receive the shank portion of said fuse-carrying unit, said compartment having a pair of terminal-forming members therein having respective external circuit connecting portions exposed to the outside of the receptacle at points to be located rearwardly of said panel and connector terminal-forming portions positioned respectively at the front and rear portions of said compartment to make electrical engagement with said front and rear terminals of said fuse-carrying unit with the fuse mounted therein when the unit is fully inserted into said receptacle, a terminal-forming member in said receptacle having wings projecting into openings in the rear portions of said receptacle-forming parts and bent to form retaining tabs which hold the rear ends of said receptacle-forming parts together, and means for holding the front parts together comprising a bezel-forming unit slidable along said confronting receptacle-forming parts to a position at the front of the receptacle where it interlocks therewith, the bezel-forming unit providing a frame around an opening in the panel in which the fuse holder receptacle is to be mounted, and means for retaining said fuse-carrying unit in said receptacle compartment at least when said unit is fully inserted therein.

19. In a fuse holder assembly for holding a fuse with terminals, the fuse holder assembly to be mounted in or behind an opening in a panel and comprising: a fuse-carrying unit with a head portion adapted to be engaged by the user's fingers and a hollow shank portion having an opening adapted to receive one end of said fuse, and means for removably retaining said fuse in said opening and forming a terminal which engages one of said fuse terminals when the fuse is positioned therein, the fuse-carrying unit with the fuse mounted therein respectively presenting front and rear terminals for electrically connecting the fuse terminals to an external circuit, the improvement in a fuse-receiving receptacle for removably receiving said fuse-carrying unit and making electrical contact respectively with said front and rear terminals of said fuse-carrying unit when said fuse-carrying unit and fuse carried thereby is inserted therein, said receptacle comprising: a pair of laterally confronting receptacle body-forming parts defining therebetween a compartment which opens onto the front of said receptacle to receive the shank portion of said fusecarrying unit, said compartment having a pair of terminalforming members therein having respective external circuit connecting portions exposed to the outside of the receptacle at points to be located rearwardly of said panel and connector terminal-forming portions positioned respectively at the front and rear portions of said compartment to make electrical engagement with said front and rear terminals of said fuse-carrying unit with the fuse mounted therein when the unit is fully in serted into said receptacle, one of said terminal-forming members in said receptacle comprising a longitudinally extending blade supported in longitudinal channels formed in at least one of the receptacle-forming parts, the other terminal-forming member in said receptacle fitting into a channel in at least one of said receptacle-forming parts and having wings projecting into openings in both of said receptacle-forming parts and bent to form retaining tabs which hold said receptacle-forming parts together, and means for retaining said fuse-carrying unit in said receptacle compartment at least when said unit is fully inserted therein.

20. In a fuse holder assembly for holding a fuse with terminals, the fuse holder assembly to be mounted in or behind an opening in a panel and comprising a fuse-carrying unit with a head portion adapted to be engaged by the user's fingers and a shank portion having an opening adapted to receive one end of the fuse, and means for removably retaining said fuse in said opening and forming at least one terminal which engages one of said fuse terminals when the fuse is positioned therein, the fuse-carrying unit with the fuse mounted therein respectively presenting front and rear terminals for electrically connecting the fuse terminals to an external circuit, the improvement in a fuse-receiving receptacle for removably receiving said fusecarrying unit and making electrical contact respectively with said front and rear terminals of said assembled fuse and fusecarrying unit when said fuse-carrying unit and fuse carried thereby is inserted therein, said receptacle comprising: a receptacle body defining a compartment which opens onto the front of said receptacle to receive the shank portion of said fuse-carrying unit, said compartment having a pair of terminal-forming members therein having respective external circuit connecting portions exposed to the outside of the receptacle at points to be located rearwardly of said panel and connector terminal-forming portions positioned respectively at the front and rear portions of said compartment to make electrical engagement with said front and rear terminals of said fuse-carrying unit with the fuse mounted therein when the unit is fully inserted into said receptacle body, the connector terminal-forming portion of one of said terminal-forming members of said receptacle body is located at the front end portion of the receptacle body and has a laterally facing aperture, and the front terminal of said fuse-carrying unit having a resilient lateral latch-forming projection which passes into said aperture when the fuse-carrying member is fully inserted into said receptacle body.

21. The fuse holder assembly of claim 20 wherein there is provided spring means in said receptacle compartment which is tensed as said fuse-carrying unit is fully inserted into said compartment and which applies an outward force against said fuse-carrying unit when held in its locked position, said fusecarrying unit being rockable about a laterally extending axis when said head portion of said fuse-carrying unit is pressed, said resilient lateral latch-forming projection moving out of said laterally facing aperture in said terminal-forming member when the fuse-carrying unit is rocked by the pressing of said head portion of said fuse-carrying member, whereupon said spring means causes longitudinal outward displacement of said resilient lateral latch-forming projection from said laterally facing aperture.

22. In combination, a panel containing a number of spaced openings for receiving fuse holder assemblies containing a fuse holder assembly for each opening comprising: a fusereceiving receptacle including means for mounting the same within the associated panel opening where the receptacle, for the most part, is physically located behind the panel, each receptacle having a fuse-receiving compartment opening onto the front of the panel, the compartment of each receptacle having a first terminal with a portion accessible from the outside of the receptacle at a point located behind said panel and a second terminal having a portion accessible from the outside of the receptacle at a point to be located behind said panel, a fuse-carrying unit with a head portion at the front thereof presenting a surface to be pressed by a user's finger and a shank portion having an opening adapted to receive a fuse and means for removably retaining the fuse in said opening, fuse connecting terminal means for connecting said fuse to said first and second terminals of said receptacle and being so positioned that when said shank portion of said fuse-carrying unit is fully inserted into said open front end of said receptacle compartment said fuse connecting terminal means engage a portion of said first and second terminals of said fuse-receiving receptacle, said surface of said head portion of said fuse-carrying unit when the unit is fully inserted into said compartment being contiguous to the front of said panel so the head portion thereof does not present any convenient shoulder for grasping and pulling the same from the fuse-receiving receptacle, and

means on said fuse-carrying unit and receptacle of each fuse holder assembly which lockingly hold said fuse-carrying unit in said compartment of said receptacle when the fuse-carrying unit is fully inserted into said compartment thereof from the front of said panel and which effects release and outward movement of said fuse-carrying unit when a portion of said surface of the head portion thereof is engaged and pressed by the end of the users finger, said outward movement of said released fuse-carrying unit permitting the same readily to be grasped and completely removed from said receptacle, and said head portions of the various fuse-carrying units of the fuse holder assemblies mounted on the receptacles thereof having varying colors to identify different portions of the circuit or circuits in which the fuses are located.

23. The fuse holder of claim 22 wherein said receptacle of each fuse holder assembly has a bezel frame on the front thereof located on the front of the panel and extending beyond the margins of the head portion of the associated fusecarrying unit to frame the same and there are different combinations of colors for the head portions of said fuse-carrying units and the bezel frames of the various fuse holder receptacles to provide a variety of color codes identifying the portions of the circuit or circuits in which the fuses of the various fuse holder assemblies are located. 

1. In a fuse holder assembly for holding a fuse with spaced terminals and to be mounted in or behind an opening in a panel, the fuse holder assembly including a fuse-receiving receptacle including means for mounting the same behind an opening in a panel where the receptacle, for the most part, is physically located behind the panel, a fuse-receiving compartment in said receptacle which opens onto the front of the receptacle, said receptacle compartment having first terminal means with a portion accessible from the outside of the receptacle at a point which is to be located behind said panel and second terminal means including a portion accessible from the outside of the receptacle at a point to be located behind said panel, the improvement comprising: a fuse-carrying unit with a head portion at the front thereof presenting a surface to be pressed by a user''s finger, a shank portion having an opening adapted to receive one end of said fuse and means for removably retaining said fuse in said opening and forming a terminal which engages one of said fuse terminals when the fuse is positioned therein, said lastmentioned terminal of said shank portion and the first and second terminal means of said fuse-receiving receptacle being so positioned that when said shank portion of said fuse-carrying unit is fully inserted into said open front end of said receptacle compartment the other terminal of said fuse is electrically connected to a portion of said first terminal means of said fuse-receiving receptacle and a portion of said terminal in the shank portion of said fuse-carrying unit engages a portion of the second terminal means of said fuse-receiving receptacle, said head portion of said fuse-carrying unit when the unit is fully inserted into said compartment being contiguous to the front end of said fuse-receiving receptacle so the head portion thereof does not present any convenient shoulder for grasping and pulling the same from the fuse-receiving receptacle, and holding means on said fuse-carrying unit and said fuse-receiVing receptacle which lockingly holds said fuse-carrying member in said compartment of said fuse-receiving receptacle when the fusecarrying unit is fully inserted into said compartment and which results in release and outward movement of said fuse-carrying unit when said surface of the head portion thereof is pressed by the end of the user''s finger, said outward movement of said released fuse-carrying unit permitting the same readily to be grasped and completely removed from said fuse-receiving receptacle.
 2. The fuse holder assembly of claim 1 wherein there is provided spring means which is compressed when said fuse-carrying unit is inserted into said compartment of said fuse-receiving receptacle, said spring means causing said outward movement of said fuse-carrying unit when released from said fuse-carrying receptacle.
 3. The fuse holder assembly of claim 2 wherein said spring means forms part of said first terminal means in said compartment of said fuse-receiving receptacle.
 4. The fuse holder assembly of claim 1 wherein said holding means include interlocking portions respectively of the terminal in said shank portion of said fuse-carrying unit and a portion of said second terminal means.
 5. The fuse holder assembly of claim 1 wherein said finger pressed surface of said head portion of said fuse-carrying unit is a transversely extending face thereof of sufficient size to present at least two distinctly different areas to be readily engaged and pressed by the end of the user''s finger, said holding means which lockingly holds said fuse-carrying unit in said compartment of said fuse-receiving receptacle effecting such locking action when one of said areas of said face of the fuse-carrying unit is pressed and effecting the release and outward movement of said fuse-carrying unit when said other area thereof is pressed.
 6. The fuse holder assembly of claim 5 wherein said areas of said face of said head portion of said fuse-carrying unit are in different planes.
 7. The fuse holder assembly of claim 5 wherein said other area of said face of said head portion of said fuse-carrying unit is a raised portion.
 8. The fuse holder assembly of claim 5 wherein there is provided spring means in said fuse-receiving receptacle compartment which is tensed as said fuse-carrying unit is fully inserted into said compartment, said holding means releasing said fuse-carrying unit when said other area of said face of said head portion of said fuse-carrying unit is pressed, said spring means then forcing said fuse-carrying unit outward.
 9. The fuse holder assembly of claim 7 wherein said raised portion extends to an outer margin of said face and there is indicia on said face of the head portion of said fuse-carrying unit which states that a portion thereof is to be pressed and there is an arrow on said face leading from said indicia and pointing to and terminating at or near said outer margin of said face.
 10. The fuse holder assembly of claim 5 wherein said other area of said face extends to an outer margin of said face and there is indicia on said face of the head portion of said fuse-carrying unit which states that a portion thereof is to be pressed and there is an arrow on said face leading from said indicia and pointing to and terminating at or near said outer margin of said face.
 11. The fuse holder assembly of claim 7 wherein there is provided spring means in said fuse-receiving receptacle compartment which is tensed as said fuse-carrying unit is fully inserted into said compartment and which applies an outward force against said fuse-carrying unit when held in its locked position, said fuse-carrying unit being rockable about a laterally extending axis when said other area of said face of the head portion of said fuse-carrying unit is pressed, and said holding means comprises a resilient lateral projection on one of the fuse-receiving receptacle and fuse-carrying unit and a laterally facing opening in the other of same, said resilient lateral projectiOn entering said laterally facing opening when the fuse-carrying member is initially fully inserted into said fuse-receiving receptacle compartment and which resilient lateral projection is moved out of said laterally facing opening when the fuse-carrying unit is rocked by the pressing of said other area of said face of the head portion of said fuse-carrying member, whereupon said spring means causes longitudinal outward displacement of said resilient lateral projection from said laterally facing opening.
 12. In a fuse holder assembly for holding a fuse with terminals on the opposite ends thereof, the fuse holder assembly to be mounted in or behind an opening in a panel, the fuse holder assembly including a fuse-receiving receptacle including means for mounting the same behind an opening in a panel where the receptacle, for the most part, is physically located behind the panel, a fuse-receiving compartment in said receptacle which opens onto the front of the receptacle, said receptacle compartment having first terminal means located at least in part in the rear end portion thereof which first terminal means has a portion accessible from the outside of the receptacle at a point which is to be located behind said panel, and second terminal means located at least in part in the front portion of said compartment and including a portion accessible from the outside of the receptacle at a point to be located behind said panel, the improvement comprising: a fuse-carrying unit with a head portion at the front thereof presenting a surface to be pressed by a user''s finger, and a hollow shank portion having an opening adapted to receive one end of said fuse and means for removably retaining said fuse in said opening and forming a terminal which engages the terminal at the adjacent end of the fuse when the fuse is positioned therein, said last-mentioned terminal and the terminal means of said fuse-receiving receptacle being so positioned that when said shank portion of said fuse-carrying unit is fully inserted into said open front end of said receptacle compartment the terminal at the other end of said fuse engages a portion of said first terminal means of said fuse-receiving receptacle and a portion of said terminal in the shank portion of said fuse-carrying unit engages the portion of the second terminal means of said fuse-receiving receptacle which is at the front portion of said receptacle, said head portion of said fuse-carrying unit when the unit is fully inserted into said compartment being contiguous to the front end of said fuse-receiving receptacle so the head portion thereof does not present any convenient shoulder for grasping and pulling the same from the fuse-receiving receptacle, and holding means on said fuse-carrying unit and said fuse-receiving receptacle which lockingly holds said fuse-carrying unit in said fuse-receiving receptacle compartment when the fuse-carrying member is fully inserted into the compartment and which effects release and outward movement of said fuse-carrying unit when said surface of the head portion thereof is engaged and pressed by the end of the user''s finger, said outward movement of said released fuse-carrying unit permitting the same readily to be grasped and completely removed from said fuse-receiving receptacle.
 13. A fuse holder assembly for holding a fuse with spaced terminals on the opposite ends thereof, the fuse holder assembly to be mounted in or behind an opening in a panel, the fuse holder assembly comprising: a fuse-receiving receptacle including means for mounting the same behind an opening in a panel where the receptacle, for the most part, is physically located behind the panel, a fuse-receiving compartment in said receptacle which opens onto the front of the receptacle, said receptacle compartment containing a first terminal-forming member having an external circuit connecting portion exposed to the outside of said receptacle at a point thereof which is to be located behind said panel and a resilient connector terminAl-forming means which is located at the rear end portion of said compartment, a second terminal-forming member in said compartment having an external circuit connecting portion exposed to the outside of said receptacle at a point thereof which is to be located behind said panel and having a connector terminal-forming portion positioned at the front end portion of said compartment; and a fuse-carrying unit with a head portion at the front thereof presenting a surface to be pressed by a user''s finger, and a hollow shank portion having an opening adapted to receive one end of said fuse and means for removably retaining said fuse in said opening and forming a terminal which engages one of said fuse terminals when the fuse is positioned therein, said last-mentioned terminal and the resilient connector terminal-forming means and said connector terminal-forming portion of said first and second terminal-forming members being so positioned that when said shank portion of said fuse-carrying unit is fully inserted into said open end of said receptacle compartment the terminal at the other end of said fuse engages said resilient connector terminal-forming means of said first terminal-forming member to deflect the same longitudinally inwardly, and a portion of said terminal in the shank portion of said fuse-carrying unit engages and interlocks with the connector terminal-forming portion of said second terminal-forming member under the outward force of said resilient connector terminal-forming means of said first terminal-forming member, said fuse-carrying unit when fully inserted into said receptacle compartment being pivotable in a direction which unlocks the interlocking portions of said terminal in the shank portion of said fuse-carrying unit and the connector terminal-forming portion of said second terminal-forming member, said head portion of said fuse-carrying unit when the unit is fully inserted into said receptacle compartment being contiguous to the front end of said fuse-receiving receptacle so that the head portion thereof does not present any convenient shoulder for grasping and pulling the same from the fuse-receiving receptacle, a portion of said surface on the head portion of said fuse-carrying unit when depressed by the user''s finger effecting said rocking of the fuse-carrying unit to release the same under the force of said resilient connector terminal-forming means which causes outward movement of the released fuse-carrying unit, permitting the same readily to be grasped and completely removed from said fuse-receiving receptacle.
 14. In a fuse holder assembly for holding a fuse with terminals, the fuse holder assembly to be mounted in or behind an opening in a panel and including a fuse-carrying unit with a head portion adapted to be engaged by the user''s fingers and a shank portion having an opening adapted to receive one end of said fuse, and means for removably retaining said fuse in said opening and forming a terminal which engages one of said fuse terminals when the fuse is positioned therein, the fuse-carrying unit with the fuse mounted therein respectively presenting front and rear terminals for electrically connecting the fuse terminals to an external circuit, the improvement in a fuse-receiving receptacle for removably receiving said fuse-carrying unit and making electrical contact respectively with said front and rear terminals of said fuse-carrying unit when said fuse-carrying unit and fuse carried thereby is inserted therein, said receptacle comprising: a pair of laterally confronting receptacle body-forming parts defining therebetween a compartment which opens onto the front of said receptacle to receive the shank portion of said fuse-carrying unit, said compartment having a pair of terminal-forming members therein having respective external circuit connecting portions exposed to the outside of the receptacle at points to be located rearwardly of said panel, said pair of terminal-forming members respectively having connector terminal-forming portions posItioned respectively at the front and rear portions of said compartment to make electrical engagement through said front and rear terminals of said fuse-carrying unit with the fuse mounted therein when the unit is fully inserted into said receptacle, and means for holding at least the front end portions of said confronting receptacle-forming parts together comprising a bezel-forming unit slidable along said confronting receptacle-forming parts to a position at the front of the receptacle where it interlocks therewith, the bezel-forming unit providing a frame around an opening in the panel in which the fuse holder receptacle is to be mounted.
 15. The fuse holder assembly of claim 14 wherein said bezel-forming unit includes outwardly expanding contractable resilient wings which, when the receptacle is pushed through a panel opening from the front thereof, first contract and then spring outwardly to lock the fuse holder receptacle in place on the panel when the receptacle has been fully inserted into the panel opening.
 16. The fuse holder assembly of claim 15 wherein said confronting receptacle-forming parts have oppositely facing longitudinally extending side walls in which are formed longitudinally extending grooves opening onto the rear ends of the receptacle-forming parts, said wings extending from said bezel-forming unit have rearwardly and outwardly inclining front portions intersecting rearwardly and inwardly inclining rear portions to form respective apexes which are normally spaced apart a distance greater than the corresponding width of the opening of the panel in which the fuse holder receptacle is to be mounted and which when flexed inwardly can clear said opening, and said wings of the bezel-forming unit slidably fit within said longitudinally extending grooves in said side walls, said apexes of said wings normally projecting beyond the side margins of the receptacle.
 17. The fuse holder assembly of claim 14 wherein said receptacle and fuse-carrying unit have a rectangular shape.
 18. In a fuse holder assembly for holding a fuse with terminals, the fuse holder assembly to be mounted in or behind an opening in a panel and comprising: a fuse-carrying unit with a head portion adapted to be engaged by the user''s fingers and a shank portion having an opening adapted to receive one end of said fuse, and means for removably retaining said fuse in said opening and forming a terminal which engages one of said fuse terminals when the fuse is positioned therein, the fuse-carrying unit with the fuse mounted therein respectively presenting front and rear terminals for electrically connecting the fuse terminals to an external circuit, the improvement in a fuse-receiving receptacle for removably receiving said fuse-carrying unit and making electrical contact respectively with said front and rear terminals of said fuse-carrying unit when said fuse-carrying unit and fuse carried thereby is inserted therein, said receptacle comprising: a pair of laterally confronting receptacle body-forming parts defining therebetween a compartment which opens onto the front of said receptacle to receive the shank portion of said fuse-carrying unit, said compartment having a pair of terminal-forming members therein having respective external circuit connecting portions exposed to the outside of the receptacle at points to be located rearwardly of said panel and connector terminal-forming portions positioned respectively at the front and rear portions of said compartment to make electrical engagement with said front and rear terminals of said fuse-carrying unit with the fuse mounted therein when the unit is fully inserted into said receptacle, a terminal-forming member in said receptacle having wings projecting into openings in the rear portions of said receptacle-forming parts and bent to form retaining tabs which hold the rear ends of said receptacle-forming parts together, and means for holding the front parts together comprising a bezel-forming unit slidable along said confronTing receptacle-forming parts to a position at the front of the receptacle where it interlocks therewith, the bezel-forming unit providing a frame around an opening in the panel in which the fuse holder receptacle is to be mounted, and means for retaining said fuse-carrying unit in said receptacle compartment at least when said unit is fully inserted therein.
 19. In a fuse holder assembly for holding a fuse with terminals, the fuse holder assembly to be mounted in or behind an opening in a panel and comprising: a fuse-carrying unit with a head portion adapted to be engaged by the user''s fingers and a hollow shank portion having an opening adapted to receive one end of said fuse, and means for removably retaining said fuse in said opening and forming a terminal which engages one of said fuse terminals when the fuse is positioned therein, the fuse-carrying unit with the fuse mounted therein respectively presenting front and rear terminals for electrically connecting the fuse terminals to an external circuit, the improvement in a fuse-receiving receptacle for removably receiving said fuse-carrying unit and making electrical contact respectively with said front and rear terminals of said fuse-carrying unit when said fuse-carrying unit and fuse carried thereby is inserted therein, said receptacle comprising: a pair of laterally confronting receptacle body-forming parts defining therebetween a compartment which opens onto the front of said receptacle to receive the shank portion of said fuse-carrying unit, said compartment having a pair of terminal-forming members therein having respective external circuit connecting portions exposed to the outside of the receptacle at points to be located rearwardly of said panel and connector terminal-forming portions positioned respectively at the front and rear portions of said compartment to make electrical engagement with said front and rear terminals of said fuse-carrying unit with the fuse mounted therein when the unit is fully inserted into said receptacle, one of said terminal-forming members in said receptacle comprising a longitudinally extending blade supported in longitudinal channels formed in at least one of the receptacle-forming parts, the other terminal-forming member in said receptacle fitting into a channel in at least one of said receptacle-forming parts and having wings projecting into openings in both of said receptacle-forming parts and bent to form retaining tabs which hold said receptacle-forming parts together, and means for retaining said fuse-carrying unit in said receptacle compartment at least when said unit is fully inserted therein.
 20. In a fuse holder assembly for holding a fuse with terminals, the fuse holder assembly to be mounted in or behind an opening in a panel and comprising a fuse-carrying unit with a head portion adapted to be engaged by the user''s fingers and a shank portion having an opening adapted to receive one end of the fuse, and means for removably retaining said fuse in said opening and forming at least one terminal which engages one of said fuse terminals when the fuse is positioned therein, the fuse-carrying unit with the fuse mounted therein respectively presenting front and rear terminals for electrically connecting the fuse terminals to an external circuit, the improvement in a fuse-receiving receptacle for removably receiving said fuse-carrying unit and making electrical contact respectively with said front and rear terminals of said assembled fuse and fuse-carrying unit when said fuse-carrying unit and fuse carried thereby is inserted therein, said receptacle comprising: a receptacle body defining a compartment which opens onto the front of said receptacle to receive the shank portion of said fuse-carrying unit, said compartment having a pair of terminal-forming members therein having respective external circuit connecting portions exposed to the outside of the receptacle at points to be located rearwardly of said panel and connector terminal-forming portions positioned respectIvely at the front and rear portions of said compartment to make electrical engagement with said front and rear terminals of said fuse-carrying unit with the fuse mounted therein when the unit is fully inserted into said receptacle body, the connector terminal-forming portion of one of said terminal-forming members of said receptacle body is located at the front end portion of the receptacle body and has a laterally facing aperture, and the front terminal of said fuse-carrying unit having a resilient lateral latch-forming projection which passes into said aperture when the fuse-carrying member is fully inserted into said receptacle body.
 21. The fuse holder assembly of claim 20 wherein there is provided spring means in said receptacle compartment which is tensed as said fuse-carrying unit is fully inserted into said compartment and which applies an outward force against said fuse-carrying unit when held in its locked position, said fuse-carrying unit being rockable about a laterally extending axis when said head portion of said fuse-carrying unit is pressed, said resilient lateral latch-forming projection moving out of said laterally facing aperture in said terminal-forming member when the fuse-carrying unit is rocked by the pressing of said head portion of said fuse-carrying member, whereupon said spring means causes longitudinal outward displacement of said resilient lateral latch-forming projection from said laterally facing aperture.
 22. In combination, a panel containing a number of spaced openings for receiving fuse holder assemblies containing a fuse holder assembly for each opening comprising: a fuse-receiving receptacle including means for mounting the same within the associated panel opening where the receptacle, for the most part, is physically located behind the panel, each receptacle having a fuse-receiving compartment opening onto the front of the panel, the compartment of each receptacle having a first terminal with a portion accessible from the outside of the receptacle at a point located behind said panel and a second terminal having a portion accessible from the outside of the receptacle at a point to be located behind said panel, a fuse-carrying unit with a head portion at the front thereof presenting a surface to be pressed by a user''s finger and a shank portion having an opening adapted to receive a fuse and means for removably retaining the fuse in said opening, fuse connecting terminal means for connecting said fuse to said first and second terminals of said receptacle and being so positioned that when said shank portion of said fuse-carrying unit is fully inserted into said open front end of said receptacle compartment said fuse connecting terminal means engage a portion of said first and second terminals of said fuse-receiving receptacle, said surface of said head portion of said fuse-carrying unit when the unit is fully inserted into said compartment being contiguous to the front of said panel so the head portion thereof does not present any convenient shoulder for grasping and pulling the same from the fuse-receiving receptacle, and means on said fuse-carrying unit and receptacle of each fuse holder assembly which lockingly hold said fuse-carrying unit in said compartment of said receptacle when the fuse-carrying unit is fully inserted into said compartment thereof from the front of said panel and which effects release and outward movement of said fuse-carrying unit when a portion of said surface of the head portion thereof is engaged and pressed by the end of the user''s finger, said outward movement of said released fuse-carrying unit permitting the same readily to be grasped and completely removed from said receptacle, and said head portions of the various fuse-carrying units of the fuse holder assemblies mounted on the receptacles thereof having varying colors to identify different portions of the circuit or circuits in which the fuses are located.
 23. The fuse holder of claim 22 wherein said receptacle of each fuse Holder assembly has a bezel frame on the front thereof located on the front of the panel and extending beyond the margins of the head portion of the associated fuse-carrying unit to frame the same and there are different combinations of colors for the head portions of said fuse-carrying units and the bezel frames of the various fuse holder receptacles to provide a variety of color codes identifying the portions of the circuit or circuits in which the fuses of the various fuse holder assemblies are located. 